27 September 2025
: Case report 
SMARCA4-Deficient Undifferentiated Carcinoma: A Report of 2 Cases
Rare disease
Sa-Hong Kim ABDEF 1,2, Kyoyoung Park D 1,2, Jane Chungyoon Kim D 1,2, Jeesun Kim D 1,2, Do-Joong Park D 1,2,3, Hyuk-Joon Lee D 1,2,3, Han-Kwang Yang D 1,2,3, Yoonjin Kwak ABDEF 4,5, Seong-Ho Kong ABDEF 1,2,3*DOI: 10.12659/AJCR.949989
Am J Case Rep 2025; 26:e949989
Figure 5 Histologic and immunohistochemical features of SMARCA4-deficient undifferentiated carcinoma with a focal adenocarcinoma component (Case 2)(A) HE staining shows a central area of undifferentiated tumor with solid growth pattern, surrounded by a poorly differentiated tubular adenocarcinoma component on both sides. (B) Cytokeratin immunostaining highlights adenocarcinoma components. (C) BRG1 expression is completely lost in the central undifferentiated area but is retained in the adjacent adenocarcinoma component.